A compressor-assisted triple-effect H2O-LiBr absorption cooling cycle coupled with a Rankine Cycle driven by high-temperature waste heat. (5th February 2017)

• Record Type: Journal Article
• Authors: Shu, Gequn; Che, Jiaqiang; Tian, Hua; Wang, Xuan; Liu, Peng
• Is Part Of: Applied thermal engineering. Volume 112(2017:Feb.)
• Page Start: 1626
• Page End: 1637
• Publication Date: 2017-02-05
• Subjects: Compressor-assisted absorption refrigeration cycle -- Rankine Cycle -- High-temperature waste heat; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2016.08.073
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: A boosting triple-effect absorption cycle powered by the Rankine Cycle is proposed. The combined cycle is fit for high temperature waste heat recovery for cooling. The combined cycle gets better performance with lower generation temperature. Generation temperature decrement is limited by the Rankine Cycle vapor pressure. Abstract: The corrosion problem caused by lithium bromide aqueous solution at high temperature limits the construction of multi-effect absorption cooling cycles. In this paper, based on the compressor-assisted absorption cycle as the bottom cycle that the predecessors had put forward to lower generation temperature, the Rankine Cycle (RC) is introduced as the top sub-cycle to supply work and heat to the bottom one in order to utilize high temperature waste heat for refrigeration efficiently. Thermodynamic calculation including exergy analysis is carried out to study the influence of some important factors, mainly high temperature generator deflation range deflation range ( ω H ) and compression ratio (CR), on the performance of the combined cycle. Simulation results show that while the maximum generation temperature is 50 °C lower than that of the traditional triple-effect cycle, the COP and cooling capacity per unit mass flow rate of the heat source still both improve more than 10% at the condition of CR = 2.2 and P vap 1 = 6.3 MPa (the Rankine Cycle evaporation pressure). Comparison with the boosting cycle with additional work input suggests the primary thermal energy conversion factor in the parameter OIR (output/input-rate) of the combined cycle is 1 and reveals the advantage of the combined cycle over the reference cycle. Because of the heat and work couple between the top cycle and the bottom cycle, only the deflation range is not very large ( ω H < 0.015 ), could the maximum generation temperature be controlled under 165 °C to get rid of severe corrosion problem. Comparison with the multistage power cycle indicates that the performance of the combined system is similar to that of the series multistage power cycle with the same number of stages.